• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.3
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• pp.204-210
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• 2009

There has been a lot of research into a background separation method, which is a preprocess of a technique of automatically perceiving an invader, and the removal of shadows around a moving object in the video monitoring field. When a moving object is not clearly separated from its shadow, it is difficult to analyze the shape accurately, and it is also hard to trace its position. This study suggests how to utilize a brightness value for removing a shadow. It came from the fact that there appears to be no change of color in the shadow area relative to the background area, and there only occurs a difference in brightness. In addition, this method uses the renewal of a critical value used for the removal of shadow in the previous frame, in the next frame.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.4
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• pp.1-8
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• 2014

In order to cope with shadow areas and to extend cell coverage, relay-assisted wireless communication systems have been widely studied. In this paper, we propose a space-frequency(SF) block coded orthogonal frequency division multiple access(OFDMA) transmission system in a relaying multi-path shadow area. The receiving performance of mobile station in a shadow area can be improved by applying SF block code to the recovered signals of multiple relays before re-transmitting them. The simulation result shows that the proposed SF block coded OFDMA transmission system considerably outperforms the conventional single-path OFDMA transmission system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.401-407
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• 2010

As according to utilizing mobile devices, the real time locating system to provide high quality service is required. RTLS based on wireless communication can be damaged from radio shadow areas which guarantee the line of sight. To cope with the radio shadow area, this paper proposes the performance improvement method using assistant tags and a directional antenna based reader. In addition, this paper also provides the design and implementation of RTLS and experiments for performance evaluation. The result shows that a success rate is increased up to 38% and accuracy is a CEP of 1.13 meters.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.409-417
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• 2013

Mu-communication board supported by multi-communication is designed with Atxmega 128A1 which is a low power energy consuming of 8-bit microcontroller. ATxmega128A1 microcontroller consists of 8 UART(Universal asynchronous receiver/transmitter) ports which can be setting appropriate user interface having command line interpreter(CLI) program with each port, 2 kbytes EEPROM, 128 kbytes flash memory, 8 kbytes SRAM. 8 URAT ports are used for the multi communication modem, GPS module, etc. and EEPROM is used for saving a configuration for program running, and flash memory of 128 kbytes is used for storing a Firm Ware, and 8 kbytes SRAM is used for stack, storing memory of global variables while program running. If we uses the hybrid communication of path optimization of VHF, TRS and CDMA to remote control AtoN(aid to navigation), it is able to remove the communication shadow area. Even though there is a shadow area for individual communication method, we can select an optimum communication method. The compatibility of data has been enhanced as using of same data frame per communication devices. For the test, 8640 of data has been collected from the each buoy during 30 days in every 5 minutes and the receiving rate of the data has shown more than 99.4 %.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1885-1894
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• 2014

There are various high-performance algorithms in the area of the existing VDSs (vehicle detection systems). However, they requires a large amount of computational time-complexity and their systems generally are very expensive and consumes high-power. This paper proposes real-time traffic information detection algorithm that can be applied to low-cost, low-power, and open development platform such as Android. This algorithm uses a vehicle's sub-shadow to set ROI(region of interest) and to count vehicles using a location of the sub-shadow and the vehicle. The proposed algorithm is able to count the vehicles per each roads and each directions separately. The experiment result show that the detection rate for going-up vehicles is 94.1% and that for going-down vehicles is 97.1%. These results are close to or surpasses 95%, the detection rate of commercial loop detectors.

• Journal of Platform Technology
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• v.10 no.1
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• pp.3-10
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• 2022

In high-risk workplaces where communication is not possible, such as deforestation, it is necessary to use equipment that monitors the worker's situation in real time and obtains information according to the worker's location in case of an emergency. This paper analyzes the development and demonstration experiments of smart hard hats for deforestation workers to maintain a safe working environment. The developed smart helmet identifies the location of the worker based on the UWB signal for location estimation, and it is necessary to keep the distance between the workers not too close. UWB, Gyro, and LoRa are used to communicate even in the communication shadow area. It is used to provide a safe working environment such as improved construction to reduce worker risks and risks in forest working environments.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.842-848
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• 2011

A fabricated hybrid control board using multi-communication is designed with a low power 8-bit microcontroller, ATxmega128A1. The microcontroller consists of 8 UART (Universal asynchronous receiver/transmitter) ports, 2 kbytes EEPROM, 128 kbytes flash memory, 8 kbytes SRAM. The 8 URAT ports are used for a multi-communication modem, a GPS module, etc. The EEPROM is used for saving a configuration for running programs, and the flash memory of 128 kbytes is used for storing a F/W (Firm Ware), and the 8 kbytes SRAM is used for stack and for storing memory of global variables while running programs. If we use the multi-communication of CDMA, TRS and RF to remotely control Aid to Navigation, it is able to remove the communication shadow area. Even though there is a shadow area for an individual communication method, we can select an optimal communication method. The compatibility of data has been enhanced as using of same data frame per communication device. For the test, 8640 of data have been collected from each buoy during 30 days in every 5 minutes and the receiving rate of the data has shown more than 85 %.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.4
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• pp.49-55
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• 2010

Cast shadow caused by an illumination condition can produce troublesome effects for face recognition system using reflectance image. Consequently, we need to separate cast shadow area from feature area for improvement of recognition accuracy. A Bilateral filter smooths image while preserving edges, by means of a nonlinear combination of nearby pixel values. Processing such characteristics, this method is suited to our purpose in illumination estimation process based on Retinex. Therefore, in this paper, we propose a new illumination normalization method based on the Bilateral filter in face images. The proposed method produces a reflectance image that is preserved relatively exact cast shadow area, because coefficient of filter is designed to multiply proximity and discontinuity of pixels in input image. Performance of our method is measured by a recognition accuracy of principle component analysis(PCA) and evaluated to compare with other conventional illumination normalization methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5776-5782
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• 2014

Relay-assisted wireless communication systems have been studied widely to cope with shadow areas and extend the cell coverage. This paper proposes a space-frequency (SF) block coded single carrier-frequency division multiple access (SC-FDMA) transmission system in a relaying multi-path shadow area and present the performance comparison of SC-FDMA systems based on the signal-to-noise power ratio (SNR) between a relay and a destination station. The performance of relaying SC-FDMA systems can be improved by applying SF block code to the recovered signals of relays before re-transmitting them. The simulation result showed that the SNR performance of the proposed SF block coded relaying SC-FDMA system was approximately 5 dB better than the SNR performance of the single-path relaying SC-FDMA system at a symbol error rate (SER) of $10^{-2}$.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.1
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• pp.15-24
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• 2010

Photovoltaic solar cells are all in the incident because they are not converted into electrical energy, high-efficiency solar cells in order to reduce the loss of elements must be. Significant factor in the loss of solar cells, optical loss and electrical loss can be divided into. Optical losses occur when the sun will be joined on the surface of the reflection, the shadow loss due to electrodes, and the losses are in the solar wavelengths. Commercialization is currently the most common solar cells on the front of the light incident on the electrode is formed. Therefore, the shadow caused by the electrode to cover the dead area of the sun, due to factors that hinder the absorption of sunlight which is shadowing them and conversion efficiency of solar cells is the inhibition factor. These barriers to eliminate the electrode linewidth reduces the shadowing to reduce, but simply of the electrode line width is reduced electrode area by reducing the series resistance elevates this because to improve the electrode Aspect ratio(height/width) to increase Ag development of paste is required. In this study, aspect ratio of screen-printing method to increase the electrode Ag paste composition of the binder for the characterization of rheology in the shadow of the electrode by reducing the optical loss of the photoelectric conversion efficiency of solar cells to boost the performance measures was. Properties and printability of the paste, the binder resin sintered characteristics that affect the thermal properties are excellent with a good screen printability acrylic resin, ethyl cellulose, using a resin were evaluated. Prepared paste rheology properties, was formed to evaluate the electrode conductivity and aspect ratio.